Desalting by Crystallization: Detection of Attomole Biomolecules in Picoliter Buffers by Mass Spectrometry

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• 作者：Xiaoyun Gong ; Xingchuang Xiong ; Song Wang ; Yanyan Li ; Sichun Zhang ; Xiang Fang ; Xinrong Zhang
• 刊名：Analytical Chemistry
• 出版年：2015
• 出版时间：October 6, 2015
• 年：2015
• 卷：87
• 期：19
• 页码：9745-9751
• 全文大小：409K
• ISSN：1520-6882

文摘

Sensitive detection of biomolecules in small-volume samples by mass spectrometry is, in many cases, challenging because of the use of buffers to maintain the biological activities of proteins and cells. Here, we report a highly effective desalting method for picoliter samples. It was based on the spontaneous separation of biomolecules from salts during crystallization of the salts. After desalting, the biomolecules were deposited in the tip of the quartz pipet because of the evaporation of the solvent. Subsequent detection of the separated biomolecules was achieved using solvent assisted electric field induced desorption/ionization (SAEFIDI) coupled with mass spectrometry. It allowed for direct desorption/ionization of the biomolecules in situ from the tip of the pipet. The organic component in the assistant solvent inhibited the desorption/ionization of salts, thus assured successful detection of biomolecules. Proteins and peptides down to 50 amol were successfully detected using our method even if there were 3 脳 10⁵ folds more amount of salts in the sample. The concentration and ion species of the salts had little influence on the detection results.